FM25/FM25X Operator’s Manual Drilling Fluid Concepts - 41
Polymer
Polymer
This drilling fluid additive provides excellent lubrication and increases viscosity in average soils and heavy
clay. In swelling clay, polymer can reduce swelling that traps pipe in the bore.
There are two types of polymer:
• long chain such as Baroid EZ-Mud
• medium chain such as Baroid Quik-Trol
Bentonite
Bentonite is a dry powder. When properly mixed with water, it forms a thin cake on bore walls, lubricating
the bore, keeping it open, and holding fluid in the bore.
Some things to remember when mixing bentonite:
• Use clean water free of salt, calcium, or excessive chlorine.
• Use water with pH level between 9 and 10.
• Use water with hardness of less than 120 ppm.
• Do not use bentonite containing sand.
• Mix bentonite thoroughly or it will settle in tank.
• Do not mix bentonite to a funnel viscosity of over 50.
For information on measuring funnel viscosity, see “Funnel Viscosity” on page 44.
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